In the United States, cancer is responsible for 25% of all deaths. Death from cancer is primarily due to metastasis of cancer cells to other organs followed by secondary tumor formation throughout the body. Breast cancer, for example, is the second-most common cause of cancer mortality among women with approximately 40,000 women and 480 men newly affected with this disease every year. Despite improved treatment options, breast cancer remains a devastating illness. There is a critical need for new predictive and diagnostic assays and treatments for breast and other solid tumor cancers.